/* replacement for asinh, acosh, and atanh */
/*
Copyright (C) 1996,2000 Free Software Foundation, Inc.
This file is part of Gforth.
Gforth is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
*/
#include <math.h>
double atanh(double r1)
{
double r2=r1 < 0 ? -r1 : r1;
double r3=log((r2/(1.0-r2)*2)+1)/2;
return r1 < 0 ? -r3 : r3;
/* fdup f0< >r fabs 1. d>f fover f- f/ f2* flnp1 f2/
r> IF fnegate THEN ;
*/
}
double asinh(double r1)
{
return atanh(r1/sqrt(1.0+r1*r1));
/* fdup fdup f* 1. d>f f+ fsqrt f/ fatanh ; */
}
double acosh(double r1)
{
return(log(r1+sqrt(r1*r1-1.0)));
/* fdup fdup f* 1. d>f f- fsqrt f+ fln ; */
}